Many products are manufactured from elongated sheet or stock material that is shipped and stored in the form of a roll or coil. Continuous strips or webs of thin, flexible material are commonly provided on storage rolls that are subsequently unwound for production of items made from these materials. Examples of these materials are plastic film, metal foil, and paper. Other materials such as cable or wire are also wound onto rolls.
During the manufacture of paper products such as napkins, newspapers, and magazines, for example, very large storage rolls of paper are used to provide the stock material from which the paper items are produced. The storage rolls are then unwound for further processing such as cutting, folding, or printing.
When a coiled roll is being unwound so that the material can be further processed, it is desirable to quickly change to a new roll once the previous roll is spent. However, the large and heavy storage rolls of stock material are difficult to handle. Also, the manufacturing process must be stopped so that the spent roll can be removed and replaced by a new roll. The time spent unloading and reloading the machine results in decreased production of the final product.
A machine that can accept subsequent or stand-by rolls of stock material that are ready to be moved quickly into an unwinding position is highly desirable because of the savings in time that such a machine would provide. The stand-by roll can be quickly moved into place, and the unwinding and subsequent processes can proceed with minimal interruption.
The placement of a roll of material onto a shaft or spindle which is then mounted onto a machine for unwinding of the roll is another time-consuming manufacturing step. The added steps of inserting the shaft into the core of the roll and then removing it when the roll is unwound result in additional time spent setting up the machine which also decreases production. A machine that can hold and unwind a roll of material without using a shaft or spindle would be advantageous.
Thus, there continues to be a need for a method and apparatus for unwinding material from a roll that allows the loading of subsequent rolls of material which are then quickly rotated into position for unwinding. Also, there is a need for a method and apparatus that will increase the speed of the unwinding process by eliminating time-consuming steps, thus increasing productivity. The present invention meets these desires.